The massive fire that engulfed the iconic Jersey shore boardwalk is considered "suspicious" and is being investigated by the Ocean County Prosecutors Office, sources told ABC News.

Officials said they are looking into all possibilities for the cause of the fire and have not yet been able to investigate because the boardwalk is still smoldering, but they believe the circumstances around the fire seem "suspicious."

Investigators are suspicious of the fire's origin for the following reasons: it was a midday fire with no bad weather to speak of or obvious cause, there were no injuries, the structure survived the summer season only to burn now and a huge number of firefighters were not around Thursday because the annual New Jersey Firemen's Convention is kicking off today in Atlantic City, sources told ABC News.

The investigation into the cause of the fire has been taken over by the county prosecutor, which officials said was a routine procedure.

"Fire of this magnitude with no obvious cause goes to the lead investigative agency in the county, which in this case is the Ocean County Prosecutor's office," one official told ABC News.

Al Della Fave, spokesman for the Ocean County Prosecutor's office, said investigators are asking the public to come forward with any videos or photos they might have shot before or during the fire to help investigators as they try to piece the circumstances together. Individuals can call 732-929-2027 with information.

Della Fave said investigators have just begun going into the fire zone to start their probe. They have started "minor sifting" of the smoldering remains and are "just getting in there now," he said.

He said that a team of investigators gathered Thursday to map out an investigative strategy, to debrief firefighters from the scene and to remind them to keep an eye out for possible evidence.

Gov. Chris Christie said during a press conference that everything will be looked at in the investigation and nothing had been ruled out yet.

The fire erupted Thursday afternoon near a Kohr's Custard Stand at the Funtown Pier on the Seaside Park boardwalk, a stretch of boardwalk that had been damaged but not destroyed during Superstorm Sandy. Heavy winds gusting at 20 to 30 mph pushed the fire north six blocks into Seaside Heights and a part of the boardwalk that was recently reconstructed after being completely destroyed during the October 2012 storm.

The stretch of sand is where a rollercoaster was lifted from the boardwalk and dropped into the ocean upright, where it stood for months after Sandy and became an iconic image of the storm's destruction.

Firefighters battled the blaze through Thursday night and into this morning, where it continues to burn but has been brought under control, according to officials. At the height of the blaze, more than 400 firefighters, many of them volunteers, were called to the scene as Seaside Park declared a state of emergency.

Crews halted the spread of the fire by bulldozing a newly-constructed part of the boardwalk, removing a 25-foot section of the new wood structure and filling in the gap with piles of sand.

Only non-serious injuries to firefighters have been reported.

"You're seeing little pockets of fire. They're just getting as much water on it as they can to try and get the smoke condition down," Ocean County fire coordinator Brian Gabriel said this morning. "We're going to be putting water on this fire because, understand, some of these buildings have collapsed."

Work crews had just completed repairs to the boardwalk destroyed by storm waters just before Memorial Day and in time for a visit from Prince Harry in May. The fire destroyed a length of boardwalk containing perhaps 30 businesses, officials said.